A. Field of Invention
This invention pertains to the art of methods and apparatuses regarding display apparatuses and more specifically to methods and apparatuses regarding the background illumination of vehicle display devices.
B. Description of the Related Art
It is known to provide electronic devices, such as head units for vehicle entertainment or audio systems, with a face plate assembly. The face plate assembly has a combination of user operable buttons that allow an operator to selectively control the electronic device. Commonly, user operable buttons are provided on a button carrier that comprises a single molded plastic piece. A front panel or bezel couples the button carrier to the electronic device. Often, the bezel is a single piece of molded plastic having a plurality of holes or apertures. Each of the bezel apertures correspond to a user operable button such that the user operable button protrudes or may be accessed through the bezel aperture. Commonly, the front panel or bezel comprises a color that may easily transmit light irradiated upon it by a light source positioned behind the bezel.
It is known to mold the user operable buttons, or areas adjacent to each of the user operable buttons, in a clear plastic or resin. An opaque or translucent paint is then applied to the user operable buttons such that when the user operable buttons are illuminated from behind by a light source, words, symbols, or other designs are displayed. Often, more than one button carrier is used, for example, a number of user operable buttons may be located on opposing sides of a display that may be provided to the electronic device for viewing visual media. The display may be viewed by an operator or vehicle occupant through a corresponding bezel aperture provided to the bezel. The display may be coupled or attached to a display carrier that is similar in composition and color to the button carrier. The bezel may also couple the display carrier to the electronic device utilizing a method similar to that used with the button carrier.
It is known to provide the face plate assembly with a printed circuit board (PCB). The PCB has a plurality of apertures through which a light source can be coupled to the PCB to provide backlighting for the button carrier, the display, and the bezel so that the electronic device may be viewed and operated during low light conditions. Commonly, the light source is a light emitting diode (LED) or other point light source. “Hot spots” or areas receiving an uneven distribution of the light emitted from the light source may occur from the use of a point light source such as a LED.
It is known to eliminate hot spots by placing a diffuser or variable light transmittance layer between the light source and the button carrier, display carrier, and the bezel. The diffuser comprises a layer of translucent material that has a pattern of opaque material upon it. The pattern of opaque material operates to diffuse the greatest amount of irradiated light in areas receiving the greatest concentration of irradiated light. Other methods include the use of lens assemblies positioned in front of the light source, reflective layers placed behind the light source, and combinations of the same.
Although known methods work well for their intended purpose, several disadvantages exist. Known methods for diffusing light emitted from a point light source require the inclusion of the separate diffusion layer, lens assemblies, reflective layers and any combination thereof within the front place assembly. Inclusion of known diffuser apparatuses comprising additional components decreases the amount of space within the front face plate assembly. Or, alternatively, the size of the front face plate assembly must be increased to provide the space required for the additional components.